one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock)
the position of greatest importance or advancement; the leading position in any movement or field; "the Cotswolds were once at the forefront of woollen manufacturing in England"; "the idea of motion was always to the forefront of his mind and central to his philosophy"
status established in order of importance or urgency; "...its precedence as the world's leading manufacturer of pharmaceuticals"; "national independence takes priority over class struggle"